In sawmill operation, the sawing of a log is frequently accomplished in a number of stages according to the operator's best estimate of log size and the number of pieces of largest size which may be advantageously obtained therefrom. Decreasing timber stands require the most efficient use of the raw material, i.e. without the excessive waste heretofore occasioned, and also the desirability of providing lumber products at fairly low cost makes more efficient methods highly desirable. A more rapid and accurate system of s wing can be of particular importance in the case of smaller logs wherein a large number of logs must be handled in order to produce a reasonable output.